Proteins are major components which constitute connective tissues of animals. In recent years, the proteins have been found to have various physiological effects such as an improvement in athletic performance, recovery from exhaustion, and prevention and amelioration of dysfunction of locomotive organs due to aging or lifestyle habits (locomotive syndrome), and hence have attracted attention as materials for a wide variety of foods and beverages.
Meanwhile, catechins have been reported to have excellent physiological actions such as a suppressive action on an increase in cholesterol and an inhibitory action on amylase activity. Thus, the catechins also have attracted attention as materials for a wide variety of foods and beverages.
In such circumstances, beverages containing proteins and catechins have been developed, and various technologies have been proposed. For example, there have been proposed: a technology for masking bitterness and astringency of gallate-type catechins and unpleasant taste of collagen by incorporating a water-soluble collagen, gallate-type catechins, and a water-soluble soybean polysaccharide at a predetermined quantitative ratio (Patent Document 1); a technology for suppressing grassy smelling derived from soybeans or milk by blending a water-soluble soybean polysaccharide, a stabilizer such as casein sodium, and gallate-type catechins in soymilk or a milk beverage, and controlling a quantitative ratio of the gallate-type catechins and solids of a soybean or a milk to a predetermined one (Patent Document 2); and a technology for suppressing decomposition of the non-polymer catechins due to heat sterilization by blending the non-polymer catechins and a water-soluble protein in a coffee extract solution in predetermined amounts, and controlling the ratio of non-epi-form catechins in the non-polymer catechins and the pH to fall within specific ranges (Patent Document 3) or the like.